/*
 * Copyright 2012-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package cn.springcloud.gray.bean.properties.source;

import java.util.Iterator;
import java.util.function.Predicate;
import java.util.stream.Stream;

import cn.springcloud.gray.bean.origin.OriginTrackedValue;

/**
 * A {@link ConfigurationPropertySource} with a fully {@link Iterable} set of entries.
 * Implementations of this interface <strong>must</strong> be able to iterate over all
 * contained configuration properties. Any {@code non-null} result from
 * {@link #getConfigurationProperty(ConfigurationPropertyName)} must also have an
 * equivalent entry in the {@link #iterator() iterator}.
 *
 * @author Phillip Webb
 * @author Madhura Bhave
 * @see ConfigurationPropertyName
 * @see OriginTrackedValue
 * @see #getConfigurationProperty(ConfigurationPropertyName)
 * @see #iterator()
 * @see #stream()
 * @since 2.0.0
 */
public interface IterableConfigurationPropertySource
        extends ConfigurationPropertySource, Iterable<ConfigurationPropertyName> {

    /**
     * Return an iterator for the {@link ConfigurationPropertyName names} managed by this
     * source.
     *
     * @return an iterator (never {@code null})
     */
    @Override
    default Iterator<ConfigurationPropertyName> iterator() {
        return stream().iterator();
    }

    /**
     * Returns a sequential {@code Stream} for the {@link ConfigurationPropertyName names}
     * managed by this source.
     *
     * @return a stream of names (never {@code null})
     */
    Stream<ConfigurationPropertyName> stream();

    @Override
    default ConfigurationPropertyState containsDescendantOf(
            ConfigurationPropertyName name) {
        return ConfigurationPropertyState.search(this, name::isAncestorOf);
    }

    @Override
    default IterableConfigurationPropertySource filter(
            Predicate<ConfigurationPropertyName> filter) {
        return new FilteredIterableConfigurationPropertiesSource(this, filter);
    }

    @Override
    default IterableConfigurationPropertySource withAliases(
            ConfigurationPropertyNameAliases aliases) {
        return new AliasedIterableConfigurationPropertySource(this, aliases);
    }

}
